Platen for printing-presses.



PATENTBD JULY 7, J. THOMSON.

PLATEN FOR PRINTING PRESSES.

APPLIOLTIOH FILED HA3. 31, 1908.

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PATENTED JULY 7, 1903.

J. THOMSON. PLATEN FOR PRINTING PRBssEs;

APPLICATION FILED MAR; 31. 1903.

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UNITED STATES Patented July 7, 1903.

PATENT OFFICE.

JOHN THOMSON, OF BROOKLYN, NEW YORK, ASSIGNOR TO JOHN THOMSON PRESS COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

PLATEN FOR PRINTING-PRESSES.

SPECIFICATION forming part of Letters Patent No. 732,797, dated July 7, 1903.

Application filed March Bl, 1903- To all whom it may concern:

Be it known that 1, JOHN THOMSON, a citizen of the United States, residing at Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Platens for Printing- Presses, of which the following is a specification.

This invention relates to the platens of platen printing-presses; and the object thereof is to increase the convenience and durability of operation and to facilitate the construction of the platen and the parts connected thereto. I

In the drawings, Figure 1 represents an embodiment of the invention in side elevation.

Fig. 2 is a side view of details. Fig. 3 is a part side and sectional view of the platen, showing details of the improved construction.

This invention relates to the movement of the platen A back and forth to and from the bed Z, Figs. 1, 2, and 3, the usual actuating means being a pair of connecting-rods 5, as shown in Fig. l and as indicated in dotted lines, Fig. 2, connecting to the platen-shaft 6. The platen is supported on horizontal seats or ways 7, formed on the frame D, bya pair of roller-wheels 8, suitably journaled, as 9, and directly mounted, one on the right 0 hand and the other on the left hand, on the inside of the guide-ears 10 of the platen, their axial centers being disposed below, distinct from and not coincident with, that of the platen-shaft. Separate means must be pro- 5 vided for controlling the movement ofthe platen under the reciprocating thrusts of the connecting-rods, and the preferred means is that of the controlling-cam 12,- connected to and moving with the platen, which I have previouslypatented; but the link-and-spring method of control is also applicable. When the platen is making the impression upon the form, additional bearing-surface is provided by the flat shoes 13 on the platen arranged to slide on the ways, and during this portion of the movement the roller-wheels are relieved from excessive pressure and, in fact, need not necessarily be in contact with the horizontal seats.

In previous practice the platen has been Serial No. 150,474. (No model.)

provided'with a pair of rockers, arcs of circles formed as a part of the platen resting upon the ways or rocker-seats, as they have commonly been termed. To finish these circular arcs requiresspecial tools, usually rocked back and forth in a lathe, and obviously the slip and wear in actual operation are confined entirely to the faces of the rockers and their supporting-seats; but by substituting the roller-wheels for the fixed 6o segmental arcs there is practically no slip or wear upon the seats or the peripheries of the wheels. The friction is reduced, the durability increased, and the difficulty and cost of construction is less. Moreover, by the use of these roller-wheels varying degrees of angle may be given to the platen simply by increasing or decreasing their diameter or by changing their axial location, and this, too, without modifying the contour of the controlling-cam or the setting of the link, whichever type of control is used, whereas when fixed arcs are used such changes can only be obtained by making new patterns and fixtures.

The fact should be borne in mind that in this type of platen there are two distinct phases to the operationfirst, the direct slide to and from the impression; second, the angular swing to deliverand receive the sheet. Hence by this construction during the direct slide to the impression the roller-wheels and controlling device are out of commission, the platen being clamped direct and solidly to the frame; but after this occurs the entire weight of the platen is borne by the rollerwheels, which simultaneously act as the fulcrum or axis of vibration of the platen and also traverse back and forth upon the ways to such an extent as the controlling device may determine. Again, the determination of any desired angle of the face of the platen with respect to the form when the platen is swung out to receive the sheet is much more readily found by this apparatus than when 5 fixed curves are used whose centers usually and necessarily describe cycloidal arcs. Finally, it may again be pointed out that the ability to increase or decrease the angle of the platen is of great practical advantage. 10

Thus by simply locating the axis of the rollers farther from the face of the platen, as to center 14, Fig. 2, the angle will be increased, while by setting the rollers toward the face of the platen, as to center 15, the angle will be decreased, which results from the change of location relative to the platen-shaft and the roller-seats.

Having described the invention, what I claim, and desire to secure by Letters Patent,

l. The combination with a frame and bed of a platen-press, a vibrating and sliding platen and means for actuating and controlling the said platen, of a pair of rollers directly mounted, one on the right-hand and the other on the left-hand sides of the platen,

below the platen-shaft, and resting upon hori-- zontal ways on the frame, the arrangement and construction being such that said rollers form the axis, and the sole means of support,

upon which the platen is vibrated, substan tially as described.

2. The combination with a frame and bed of a platenpress, a vibrating and sliding platen and means for actuating and controlling the said platen, of two supporting rollerwheels, directly mounted upon the inside of the platen-ears, one at the right hand and the other at the left hand, below the platen-shaft, and upon which the platen is solely supported vibrated and reciprocated before and after the direct slide to and from the impression, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

JOHN THOMSON.

lVitnesses:

F. L. FREEMAN, G. P. KRAMER. 

